Musicians playing electronic instruments may alter the sound of the instrument by modifying properties of the instrument's electronic signals using devices that receive the electronic signal prior to being recorded and/or amplified and passed to a speaker. Effect pedals may be a sound-altering device favored by guitar players because it can be foot-operated. A basic effects pedal may include a footswitch, one or two potentiometers, and a power indicating lamp. The effects pedal may modify the sound of various effects including distortion, overdrive, fuzziness, noise reduction, etc.
Distortion and overdrive units distort the tone of an instrument by adding overtones—i.e., a frequency higher than the fundamental frequency. A gritty sound may be added using a unit that reshapes or clips the sound signal, so that they have a flat peak as opposed to a rounded one. Distortion effect units may produce roughly the same amount of distortion at any volume. Overdrive effect units may produce a cleaner sound at lower volume and a distorted sound at higher volume. One type of distortion unit is a fuzzbox which may clip a sound wave to almost a square wave appearance, thereby producing a signal with heavy (e.g., fuzzy) distortion.